The present invention relates to a new and distinct cultivar of hibiscus, botanically known as Hibiscus rosa-sinensis and hereinafter referred to by the cultivar name ‘DUP-CMIP.’
Hibiscus have been the subject of human admiration for centuries. While the ancestry of present rosa-sinensis hybrids is not precisely known, today's hybrids are thought to be the products of interspecific crosses involving Hawaiian, Polynesian and Asian species, among others, some of which may no longer be found in the wild, if they are to be found at all. It is thought that the first hibiscus identified as a rosa-sinensis was a double red form of uncertain origin found in cultivation in China, India and Polynesia, to be later introduced to Hawaii from Polynesia. It is known to have been grown in Europe during the Victorian era. Eventually, it was introduced to the continental United States where it was cultivated outdoors in the Deep South as well as in regions having subtropical or Mediterranean climates (Florida and Southern California, respectively). Indoor cultivation took place in the temperate regions of the U.S. It is speculated that the original rosa-sinensis is actually a species hybrid, possibly naturally arising, involving two or more species. Regardless, present day hybrids are descended from the original double form, and are thought to include in their ancestry Hibiscus liliiflorus, H. arnottianus, H. schizopetalus, as well as other species, particularly those native to Hawaii.
Today, after decades of extensive hybridization, the moniker “rosa-sinensis” almost certainly denotes complex interspecific hybrids. Such hybrids are usually far removed from their species ancestors in form and color. Flowers characterized by spectacular size, color intensity and, in the last several decades, ringed and spotted patterns have been produced by U.S. hybridizers in Louisiana, Florida, Hawaii, Texas and elsewhere. Other hotbeds of hibiscus-breeding activity include Australia, and more recently, Tahiti. Today's flowers are removed from their species ancestors to such an extent that it is almost impossible to unravel the species component contributions which comprise a modem hybrid hibiscus. 
However, in the past, despite the fact that hybridization was giving rise to flowers of spectacular size and color intensity, very few if any early hybrids attracted the attention of large scale commercial propagators. While the flowers were truly some of the most impressive in the entire plant world, hybridizers had been selecting predominantly for bloom characteristics. As a result, many of these spectacular hybrids were weak plants which, even with the best care, were short-lived and difficult to grow. The occasional production of a spectacular bloom was enough to keep the interest of those truly dedicated to growing something rare and special, and thus new hybrids continued to be produced by hobbyists with abundant passion and small amounts of greenhouse space. As a result, more breathtaking varieties were produced each year, to be distributed via grafting among dedicated hobbyists, only to die out within a time span of 10 or 15 years. It should be noted that the majority of the varieties introduced in the 1960's, 70's and even many from the 1980's and 90's are likely to be lost to cultivation, if they are not already.
Progress toward the development of a plant which an average gardener could easily grow and enjoy was slow to non-existent. Many varieties were difficult to root from cuttings, and even if they did root, many varieties, when grown on their own roots, were extremely susceptible to fungal and bacterial root rots. Some grew acceptably only as grafted plants. However, grafted plants suffer from a serious disadvantage in that the quality of the graft generally determines the quality of the plant, making the production of uniformly vigorous plants a difficult task. Furthermore, after several years, it is common for grafted plants to develop stresses at the graft union due to the unequal growth rates of the rootstock and the scion. Such stresses can eventually lead to loss of vigor and death of the plant. Moreover, grafting does not completely cure the problem of root rot; surprisingly, the rootstock, when grafted to a root rot susceptible scion was generally still more likely to suffer rot than a plant of the rootstock variety. For example, a plant of ‘Seminole Pink’, a garden variety commonly used as a rootstock, is highly resistant to root rot. However, when ‘Seminole Pink’ is used as a rootstock for ‘Romeo’, a modern hybrid which is prone to root rot, the grafted plant, while less susceptible than ‘Romeo’, is more susceptible than a plant of ‘Seminole Pink’.
Perhaps the most detrimental disadvantage of grafted plants is the introduction of viruses into the scion from the rootstock. Rootstock varieties are almost invariably old garden varieties which, over the years, have become infected with multiple viruses. While the performance of such vigorous garden varieties may be largely unaffected by virus infection, the hybrid scion of a grafted plant has generally been significantly less vigorous than the garden variety rootstock, and virus infection from the rootstock resulted in a weak plant. The problem only increased with successive generations of grafting, resulting in a rapid general weakening of a given variety over time.
Because many hybrids are shy bloomers at best, the extra stresses due to virus infection, grafting, low disease resistance, and the like generally gave sparse flower production, as well as a high number of deformed blooms. Furthermore, ordinary stresses such as over/under watering and mite/insect pests resulted in a high percentage of bud drop. The buds of large-flowered hybrids often take relatively long times to reach blooming stage, and it was not uncommon to wait with anticipation while a bud swelled day by day, only to be disappointed when the mature bud toppled from its pedicel on the day it was to open.
Moreover, because of hybridizer emphasis on the flower, the plant was often relatively slow growing and sparsely clothed in leaves. Such plants usually do not attract purchasers as they do not have the appearance of garden-worthy specimens.
It has been noted in the industry that a hybrid hibiscus seems to sell only when it is bearing a bloom. The practical effect of all of the above-mentioned issues on a retail outlet is as follows. A garden center will order a number of plants. Many of the plants will arrive either in bloom or up to several days away from blooming. The blooming plants will generally sell the first day. On several subsequent days, new blooms will open on the remaining plants, and some of them will sell as well. However, by the fourth or fifth day, the lack of perfect growing conditions begins to take a toll, and the plants begin to drop their most mature buds. From this point on, the plants essentially sit around until they are marked down or even until they decline to such a degree that they must be discarded.
Such characteristics left hibiscus with the reputation that, despite the mesmerizing beauty of the flowers, they were for collectors who had time to attend to the seemingly exacting requirements of the plants. As a result, while new varieties were produced by hobbyists yearly, propagation of modem hybrids on a commercial scale was generally rare. Common garden varieties (‘Seminole Pink’, ‘Brilliant’, ‘President’, ‘Painted Lady’, ‘Butterfly’, and ‘Lagos’, for example), which are easy to root, fast growing, and tolerant of a wide range of growing conditions were the only hibiscus widely available. The “exotics” were of little interest to commercial growers.
Many new varieties of hibiscus representing a vast improvement in rosa-sinensis hybrids, have been produced by an intense hybridizing program conducted by the Inventor at his commercial nursery in Plaquemine, La. The objective of the program has been to produce varieties of hibiscus which root easily under commercial rooting conditions, grow well on their own roots, maturing rapidly into well-leaved, salable plants under commercial greenhouse conditions. Further objectives have been to produce hibiscus cultivars as aforementioned, having large flowers with unique and desirable flower characteristics, such as size, color intensity and pattern.
The inventor has been successful in accomplishing the aforementioned objectives. However, in recent years, likely at least partly as a result of the availability and rising popularity of the inventor's exotic hibiscus which can be grown in gardens and large pots, a demand has arisen for reduced-size hibiscus plants which can be grown in small pots, such as, for example, standard 5, 6 or 8-inch diameter pots. While small hibiscus in five or six inch pots were produced as long ago as the early eighties, the plants used were full-size varieties chemically dwarfed to a height in the range of from about 6 to about 12 inches by the use of growth regulators. Growth regulators are used in the ornamental plant industry to chemically “dwarf” a plant. A widely-used growth regulator is Cycocel™. Once a hibiscus plant is exposed, subsequent stem-lengthening processes slow dramatically; one effect of Cycocel™ is to prevent the lengthening of internodes. Exposure also causes existing stems, leaves and petioles to thicken such that the plant has a sturdy, stocky appearance, and branch tips bear an attractive crown of closely-spaced leaves. These crowns add new leaves at a much slower rate than unexposed plants. As buds mature, the reduced flexibility of the shortened, thickened flower peduncle causes them to thrust above the leaf crowns, giving opened flowers an upwardly-facing orientation which maximizes their display on a small plant which is generally viewed from above. Without treatment, the natural flower orientation of most varieties is outward or slightly downward. The effect of Cycocel™ is to maintain a dwarf stature while allowing a succession of blooms which are mostly from buds set prior to the application. While the hibiscus plant is under the influence of Cycocel™, the production of new flower buds is extremely slow. Thus, in the case of hibiscus, Cycocel™-exposed plants do not perpetually produce flower buds and are thus generally discarded once blooming ceases unless one is willing to wait for the effects of the Cycocel™ to abate, which can be as long as a year or more. With a heavy exposure, some plants ultimately die before the effects abate, further underscoring the disposability aspect.
With the recently increased popularity of standard-sized exotic hibiscus varieties, the demand for smaller-sized plants with upturned, proportionally-sized flowers has increased well above what it was in the 1980's. Recently, new varieties of hibiscus having flowers in the 4.0 to 6.5 inch diameter range have become widely available as six inch pot plants. Regardless of whether the varieties were developed for use in small pots, they generally have a growth habit which is similar to the standard varieties from which they were developed. Thus, they must generally be treated with Cycocel™ in order to be used as six inch pot plants. Without treatment (or after the abatement of the treatment effects), most of them rapidly become standard-sized plants, even appropriate for larger uses such as patio trees and large pot plants. Once plants outgrow the growth regulator effect, the blooms are produced with the more natural outward or downward orientation.
It is also noted that these newest varieties, which are deemed to be more suitable than older garden varieties for use as small pot plants, are apparently largely derived from these older varieties. As such, they bear blooms characteristic of garden varieties. The flowers are of a crepe paper-like constitution, usually lacking the thick texture of the exotic hybrid varieties. Ringed and spotted patterns, as well as the expanded palette of unusual colors and color combinations prevalent in the exotics are not available in the varieties currently used as chemically-dwarfed pot plants. Another feature distinguishing the exotics, a flat, fully-opened disposition, is generally not achieved, with the flowers of the currently available plants having a widely-flared shape common with garden varieties. That the newest varieties for six inch pots lack the features of the exotic hybrid varieties might seem surprising; one reason for the intense renewed interest in hibiscus is the development of garden-worthy full-size exotic hibiscus. However, the use of Cycocel™ on exotics is less reliable due to the fact that, while the exotics produced by the inventor are sturdy, they are not as adaptable to treatment with growth regulators as garden varieties. The foregoing is particularly true considering the degree of treatment required to limit growth to a 6 inch pot.
Hibiscus varieties having the flower dispositions, colors, color combinations and patterns characteristic of the exotics, in a plant habit suitable for culture in a small (5 to 8 inch diameter) pot without the application of growth regulators such as Cycocel™ would represent an advance in the ornamental plant industry.
The inventor has produced varieties of hibiscus which are of dwarf stature without the use of growth regulators, and which produce flowers having characteristics of exotic hibiscus varieties, such as unusual colors and/or patterns. ‘DUP-CMIP’ is a seedling selection which resulted from the controlled pollination of ‘Sweetie’, the seed parent, with ‘Cosmic Ray’, the pollen parent. Asexual reproduction of the new hibiscus by hardwood, semi-hardwood, and terminal cuttings taken in a controlled environment in Plaquemine, La., has shown that the unique features of this new hibiscus are stable and reproduced true to type in successive generations.